#!/bin/sh
# send mail script for adblock notifications
# Copyright (c) 2015-2020 Dirk Brenken (dev@brenken.org)
# This is free software, licensed under the GNU General Public License v3.

# Please note: you have to manually install and configure the package 'msmtp' before using this script

# set (s)hellcheck exceptions
# shellcheck disable=1091,2010,2016,2034,2039,2059,2086,2091,2129,2143,2154,2181,2183,2188

LC_ALL=C
PATH="/usr/sbin:/usr/bin:/sbin:/bin"

if [ -r "/lib/functions.sh" ]
then
	. "/lib/functions.sh"
	adb_debug="$(uci_get adblock global adb_debug "0")"
	adb_mailsender="$(uci_get adblock global adb_mailsender "no-reply@adblock")"
	adb_mailreceiver="$(uci_get adblock global adb_mailreceiver)"
	adb_mailtopic="$(uci_get adblock global adb_mailtopic "adblock notification")"
	adb_mailprofile="$(uci_get adblock global adb_mailprofile "adb_notify")"
fi
adb_ver="${1}"
adb_mail="$(command -v msmtp)"
adb_logger="$(command -v logger)"
adb_logread="$(command -v logread)"
adb_rc=1

f_log()
{
	local class="${1}" log_msg="${2}"

	if [ -x "${adb_logger}" ]
	then
		"${adb_logger}" -p "${class}" -t "adblock-${adb_ver}[${$}]" "${log_msg}"
	else
		printf "%s %s %s\\n" "${class}" "adblock-${adb_ver}[${$}]" "${log_msg}"
	fi
}

if [ -z "${adb_mailreceiver}" ]
then
	f_log "err" "please set the mail receiver with the 'adb_mailreceiver' option"
	exit ${adb_rc}
fi

if [ "${adb_debug}" -eq 1 ]
then
	debug="--debug"
fi

adb_mailhead="From: ${adb_mailsender}\\nTo: ${adb_mailreceiver}\\nSubject: ${adb_mailtopic}\\nReply-to: ${adb_mailsender}\\nMime-Version: 1.0\\nContent-Type: text/html\\nContent-Disposition: inline\\n\\n"

# info preparation
#
sys_info="$(strings /etc/banner 2>/dev/null; ubus call system board | sed -e 's/\"release\": {//' | sed -e 's/^[ \t]*//' | sed -e 's/[{}\",]//g' | sed -e 's/[ ]/  \t/' | sed '/^$/d' 2>/dev/null)"
adb_info="$(/etc/init.d/adblock status 2>/dev/null)"
if [ -f "/var/log/messages" ]
then
	log_info="$(awk '/adblock-/{NR=1;max=79;if(length($0)>max+1)while($0){if(NR==1){print substr($0,1,max),"&#8629;"} else {print " ",substr($0,1,max)}{$0=substr($0,max+1);NR=NR+1}}else print}' /var/log/messages)"
elif [ -x "${adb_logread}" ]
then
	log_info="$("${adb_logread}" -e "adblock-" | awk '{NR=1;max=79;if(length($0)>max+1)while($0){if(NR==1){print substr($0,1,max),"&#8629;"} else {print " ",substr($0,1,max)}{$0=substr($0,max+1);NR=NR+1}}else print}')"
fi

# mail body
#
adb_mailtext="<html><body><pre style='display:block;font-family:monospace;font-size:1rem;padding:20;background-color:#f3eee5;white-space:pre'>"
adb_mailtext="${adb_mailtext}\\n<strong>++\\n++ System Information ++\\n++</strong>\\n${sys_info}"
adb_mailtext="${adb_mailtext}\\n\\n<strong>++\\n++ Adblock Information ++\\n++</strong>\\n${adb_info}"
adb_mailtext="${adb_mailtext}\\n\\n<strong>++\\n++ Logfile Information ++\\n++</strong>\\n${log_info}"
adb_mailtext="${adb_mailtext}</pre></body></html>"

# send mail
#
if [ -x "${adb_mail}" ]
then
	printf "%b" "${adb_mailhead}${adb_mailtext}" 2>/dev/null | "${adb_mail}" ${debug} -a "${adb_mailprofile}" "${adb_mailreceiver}" >/dev/null 2>&1
	adb_rc=${?}
	f_log "info" "mail sent to '${adb_mailreceiver}' with rc '${adb_rc}'"
else
	f_log "err" "msmtp mail daemon not found"
fi
exit ${adb_rc}
